UPDATE II: Sen. John Cornyn, Texas Republican, issued his own letter to Peake as well. You can read it here.

The government is testing drugs with severe side effects like psychosis and suicidal behavior on hundreds of military veterans, using small cash payments to attract patients into medical experiments that often target distressed soldiers returning from Iraq and Afghanistan, a Washington Times/ABC News investigation has found.

In one such experiment involving the controversial anti-smoking drug Chantix, the Department of Veterans Affairs (VA) took three months to alert its patients about severe mental side effects. The warning did not arrive until after one of the veterans taking the drug had suffered a psychotic episode that ended in a near lethal confrontation with police.

James Elliott, a decorated Army sharpshooter who suffers from post-traumatic stress disorder (PTSD) after serving 15 months in Iraq, was confused and psychotic when he was Tasered by police in February as he reached for a concealed handgun when officers responded to a 911 call at his Maryland home.

For photos, video of James Elliott, official FDA documents and more, visit the interactive site for theDisposable Heroes report.

Mr. Elliott, a chain smoker, began taking Chantix last fall as part of a VA experiment that specifically targeted veterans with PTSD, opting to collect $30 a month for enrolling in the clinical trial because he needed cash as he returned to school. He soon began suffering hallucinations and suicidal thoughts, unaware that the new drug he was taking could have caused them.

Just two weeks after Mr. Elliott began taking Chantix in November, the VA learned from the Food and Drug Administration (FDA) that the drug was linked to a large number of hallucinations, suicide attempts and psychotic behavior. But the VA did not alert Mr. Elliott before his own episode in February.

In failing to do so, Mr. Elliott said, the VA treated him like a “disposable hero.”

“You’re a lab rat for $30 a month,” Mr. Elliott said.

One of the nation’s premier medical ethicists said the VA’s behavior in the anti-smoking study violated basic protections for humans in medical experiments.

“When you’re taking advantage of a very vulnerable population, people who have served the country, and the agency that’s responsible for their welfare isn’t putting their welfare first, that’s a pretty serious breach of ethics,” said Arthur Caplan, director of the Center for Bioethics at the University of Pennsylvania.

In all, nearly 1,000 veterans with PTSD were enrolled in the study to test different methods of ending smoking, with 143 using Chantix. Twenty-one veterans reported adverse effects from the drug, including one who suffered suicidal thoughts, the three-month investigation by The Times and ABC News found.

Mr. Caplan, who reviewed the consent and notification forms for the study at the request of The Times and ABC News, said the VA deserved an “F” and that it has an obligation to end the study, given the vulnerability of veterans with PTSD and the known side effects of Chantix. “Continuing it doesn’t make any ethical sense,” he said.

The VA continues to test Chantix on veterans, even as reported problems with the drug increase and have prompted at least one other federal agency to take action. On May 21, the Federal Aviation Administration banned airline pilots and air traffic control personnel from taking Chantix, citing the adverse side effects.